Donald b



June 14, 1932. B. KNIGHT REFRIGERATION Original Filed May 24, 1923 2 Sheets-Sheet umiW.

avwentoz I June 14, 1932. D, KNIGHT Re. l 8,494

REFRIGERATION Original Filed May 24, 1928 2 Sheets-Sheet 2 anvemtoz Reissued June 14, 1932 PATENT, OFFICE 901mm) IB. xmen'r, or vaaooxmnsr, miw Yoax anrmennarrou Original No. 1,748,957, dated larch 4, 1930, Serial no.

250,139, fled m 24, ms. Application to:

reissue filed April 16, 1981. Serial No. 530,700.

This invention relates to the system of refrigeration described the United States No. 1,609,334, dated December 7 1926, In that system, as disclosed in said Letters Patent, the development of internal pressure is a necessary incident. requires the apparatus to be so constructed as to be'capable. of resisting such pressure, with consequent expense. It also subjects the 10 apparatus to restrictions imposed by local communities and to regulations of the Interstate Commerce Commission governing the use and shipment of compressed gases. It

creates sales resistance due to fancied or real dangers attending the use of ases under compression. It requires carefu tests to insure reasonable safet It' involves service .cost due to leakage. t requires expenditure of time and labor in charging the apparatus and in purging it. It is the object of'the present invention to enable refrigeration by methods of the eneral character of that described in said tters Patent to be carried on at atmospheric pressure, without the development of internal pressure of material degree in any part of the apparatus andwithout subjection to such objections as have been described above.

It is a further object to carry on this method so ofrefrigeration so that two refrigerating temperatures are obtained a low temperature which is available, if so desired, for the purpose of freezin ice, and ahigher temperature which is avai able for the preservation of foods.

, By the use of these two temperatures,..ob-

tained by the process herein described, frost need not collect u on the outer walls of the evaporator and tihe necessity of shutting down the machine at intervals in order to defrost the evaporator may be eliminated. Furthermore, foods may be preserved-in a fresher condition inasmuch as the moisture is'not distilled from them by excessively low evaporator temperatures. A. greater efliciency is also obtained in the operation of the system as will be later explained and, as will also be later explained, the evaporation at two temperatures provides a method W whereby refrigeration of this general charin Letters Patent of This acter may be carried on successfully at atmospheric pressure. I

In accordancewith the invention the cooling agent employed is of relatively low vapor.- pressure and is evaporated in the presence of an inert auxiliary agent at atmospheric pressure, the circulation of the auxiliary agent being accomplished also under substantially atmospheric pressure, by difference in specific weights of vertically extending bodies of fluid in the system. It will be seen that the invention is characterized by the employment of a cooling agent of relatively low vapor pressure, such, for example, as ether an absorbent such, for example,-'as a solution of ether in phenol or kerosene, and an auxiliary agent, such, for example, as nitrogen or atmospheric air, into which andin the presence of which the ether difiuses and evaporates, all under atmospheric pressure.

In the practice of the invention the following conditions should be established. The refrigerating fluid should be condensible at atmospheric pressure at a temperature, such as normal room temperature, easily reached with the available cooling water or othercon- 'densing means. The auxiliar agent should be lighter per unit volume t an the vapor. I

of the refrigerating fiuidand chemicall inert to it. The absorption medium 'shou d be such that at atmos heric pressure it will absorb the vapor of the refrigerating fluid even though it is greatly diluted by the auxiliary fluid, it being apparent that if the auxiliary agent has a great efiect upon the .ability of the refrigerating fluid. toevaporate in the evaporator, it will have the same tendency in the absorber. The auxiliary agent should circulate in a comparatively large volume in order that a suflicient amount of refrigeration may be obtained at lowtemperature with a liquid of relatively high boiling point; The refrigerating fluid is a sovery dilute in the auxiliary agent at low evaporator temperatures and a powerful absorbent fluid is required for its renewal. The process must be carriedon in such manner-that the refriger-' ating fluid will be evaporated in suflicient uantity to realize a practical amount of rerigeration.

It will be noted here that it is characteristic of liquids which boil at temperatures rator is therefore of importance. 'Because' of the absence of pressure it must be large and offer a large cooling surface to the refrigerating chamber. During the period when a relativelylow temperature is required for the formation of ice independently of the cooling of the refrigerating chamber, the refrigerating chamber might become too cold by reason of the large cooling surface to which it is exposed and the present system therefore also involves a method of two-temperature refrigeration in order to prevent such result.

The design of the evaporator is of further im portance, particularly with a View to the prevention of the formation of a protective blanket of vapor which would tend to prevent the auxiliary agent from performing its function. As will be seen hereinafter, the evaporator shown and described herein has been designed to meet this condition.

The invention will be more fully explained with reference .to the accompanying drawin s in which it is illustrated andin which:

igure 1 is a somewhat diagrammatic view, in sectional elevation, showing a form of apparatus. adapted for the practice of the invention.

Figure 2 is a detail view showing the construction and arrangement of the evaporator as seen from above, with the top removed.

Figure 3 is a detail view in perspective illustrating particularly the connection of one of the trays of the refrigerating chamber to the ice chamber.

Figure 4 is a detail view in perspective of one of the asbestos sheets which forms the bottom of one of the trays of the refrigerating chamber as seen-from below, with its frame.

Figure 5 is a detail view illustrating the construction and arrangement of the refrigerating chamber, ice chamber and trays, as seen from the right-hand in Figure 1 with the end wall removed.

Figure 6 is a detail view illustrating the arrangement of the trays in the absorber.

Figure 7 is a fragmentary view showing the application of cooling water pipes to the trays in the absorber.

The cooling agent, which for purposes of explanation of the nature of the invention and by way of example only, may be taken to be ether, may be introduced into the appa-' ratus, in solution with the absorption lilqlulor, such as phenol or kerosene, through a 'ng plug conveniently located, as at a in an absorber A, and the auxiliary agent, which nay also be taken, for purposes of explanation and by way of example only, to be nitrogen or atmospheric air, may be introduced into the apparatus at any convenient point as through the vent pipe 11 which at its openupper end terminates above the rest of the apparatus. By a suitable source of heat, indicated at 14, the solution of cooling agent and absorption liquor is heated and is caused to rise through a pipe 11 to the upper part of a separator K which is independent of the generator K and in which the vapor of the heated cooling agent is separated from the absorption liquor, such as phenol or kerosene, for example, which is in solution with the ether or its functional equivalent. From the separator K the vapor of the cooling agent passes upward through the pipe 11 which may include at E a. rectifier'by which any vaporof the absorption liquor which may have been carried upward with the vapor of the cooling agent is condensed and separatedto be returned to the separator K Substantially at the highest point of the apparatus the vapor of the cooling agent enters a condenser C within which is a pipe B suitably connected to a continuous supply of cooling water.

The condensed vapor, which is rich in ether or its equivalent, is conducted from the condenser C through the pipe 12 to the evaporator G which is placed within the refrigerating chamber, indicated at G. The preferred construction of the evaporator will be described more fully hereinafter. For present purposes it will be suflicient to say that the construction of the evaporator is such that.

the evaporation of the cooling agent proceeds rapidly in the presence of the auxiliary agent,

7 such as air or nitrogen, with consequent absorption of heat and refrigeration. Y

By reason of the fact that the density of the vapor of the cooling agent is greater than the density of the auxiliary agent the mixture of the two vapors has a density greater than the density of the auxiliarv agent. Therefore, the mixture of the vapor of the cooling agent and the auxiliary agent passes downward through, the pipe M from the evaporator and enters the lower part of the absorber A through the extension M The pipe M preferably encloses an inner pipe N through which the relatively lighter auxiliary agent passes upward from the absorber A to the upper part of the evaporator G, This move- .ment of the two gases is due to the fact that the column of vapor in the pipe M is heavier 'the required amount of refrigeration is small the evaporator temperature will fall, less of the cooling agent will be diffused intothe auxiliary agent and the movement of the two gaseous columns will necessarily be slower. Thus the rate of circulation'of the auxiliary agent between the evaporator and.the absorber is controlled in accordance with the refriger. ting effect required with subsequent economy. The space between the ipe M and the inner pipe N is refrigerated y the cold vapors issuing from the evaporator G, and the warmer and lighter gases passing upward from the absorber A are constantly giving up their heat to the cold vapors in the space between the pipes M and N.

In the illustrated embodiment of the invention the pipes M and N form a heat exchanger by means of which the auxiliary agent is cooled as far as possible bythe gases which leave the evaporator in order to avoid refrigeration loss, but it is apparent that the space between the pipes M and N is essentially a refrigerated space whereto refrigeration is delivered and wherein such refrigeration is usedup in reducing the temperature of a heat emanating source; a characteristic of this refrigerated space being that the refrigeration is delivered thereto by the circulation through the enclosure of the mixed vapors of the auxiliary agent and the cooling agent issuing from the cold evaporator. It is to be observed that the cooling agent, at the time of its diifusion in the presence of the auxiliary agent, is in itself of relatively low vapor pressure andhas no substantial admixture of any absorbent which thereby would prevent the proper operation of the improved process set forth herein.

Within the absorber A the solution of the cooling agent and the absorption liquor takes place, the construction of the absorber, as will be explained more fully hereinafter, being such that the concentration of the solution progresses.

The absorption liquor is delivered to the absorber A fromthe separator K through the pipe P connected to the separator K near its lower end, a heat exchanger T, and a prerooler X, from which theabsorption liquor, poor in cooling agent, is delivered through the pipe P to the upper part of the absorber A, passing by gravity to the lower part of-the absorber and becoming progressively concentrated.

From the absorber A the concentrated solution passes through a pipe L. the externalportion of the heat exchanger T, and the pipe extension L back to the generator K where the'cycle begins its repetition. The pipe L is preferably extended upward within the absorber for a short distance as represented in the drawings in order that the concentrated liquor may accumulate to a moderate depth in the absorber, the absorption of the coolin agent, in its richest condition, being carried on at the surface of the liquor in the lower part of the absorber.

It being one purpose of the present invention to permit the refrigeration to be carried on at substantially atmospheric pressure, connection from the absorber to the atmosphere is established through the vent pipe (1, the open upper end of which, previously stated, terminates above the rest of the a'p-.

paratus.

To equalize the pressure in the several parts of the apparatus, to prevent the building up of pressure on'the generator side, and to permit the escape of air which may be carried over with the vapor from the generator, a direct vapor connection between the vapor space of the condenser C and the evaporator is established through a pipe'c.

It being very desirable that evaporation of the cooling agent shall proceed as rapidly as possible in the evaporator, the construction of the evaporator shown in Figures 2, 3, 4 and 5 is preferred. As shown particularly in Figure 2, the evaporator is formed with two win 5 or parts G and G which are substantial y identical in construction and receive between them the ice chafnber H in which ice comprises a series of horizontal trays g which may be secured by solder or otherwise to the walls of the ice chamber H. Each tray is formed on its upper side with a flange g and with a series of relatively large openings g'-', which are closed from the underside by a sheet 9 of asbestos or other suitable material, which may be of such texture as will permit the liquid to seep through while at the same time it saturates the sheet secured to the underside of the tray by a light frame g, which may be secured to the tray in any convenient manner, as by bolts at 9 The cooling agent is delivered by a branch 12 or 12 to the uppermost tray of each series and.

through the openings 9 saturates the asbestos sheetfrom the'underside of which evapora-' tion of the cooling agent proceeds rapidly, without the formation of a protecting blanket, the vapor thus disengaged at atmospheric pressure passing down through the pipes M.

agent and the evaporated refrigerant, which are poor conductors of heat, the heat from the'refrigerating chamber G passes through the walls of'the evaporator G, and warms the vapors contained therein, but is retarded by the vapors in its passage to the trays y, passing to the evaporating liquid at a slower rate per degree temperature difference than the heat from the ice chamber H to the evaporating liquid. The trays 9 therefore are maintained at a relatively'low'temperature as compared tothe outer shell of the evaporator. This facilitates the freezing of the ice in the chamber H.

After cooling the ice chamber H, the refrigerating liquid drops from the lowest tray into the bottom of the shell of the evaporator G and here makes good thermal. contact with the refrigerating chamber G The auxiliary agent, which is saturated with the vapor of the refrigerant at the temperature of the ice chamber H, passes also downward, and permits vaporization of the refrigerant in the bottom of the evaporator at the relatively high temperature available due to the heat from the chamber G In this way the auxiliary agent is permitted to carry a greater percentage of refrigerant vapor with it to the absorber than if all the evaporation were accomplished at the low temperature required by the ice'chamber H. The efiiciency of the unit is raised cor respondingly as it is clear that the smaller the quantity of auxiliary agent that must be cooled in the evaporator'and again heated up in the absorber, the smaller will be the loss sustained. Moreover, additional efficiency is obtained in that the auxiliary agent is not cooled all the way to the temperature of the refrigerating liquid in passing through the evaporator but is kept relatively warm by the heat from the refrigerating chamber G with which it makes contact as already described. In this way a smaller quantity of refrigeration is carried away and lost in the absorber. I

It is apparent that the two temperature effect will exist whether or not an excess of refrigerating-liquid reaches the bottom of the evaporator G, forthe refrigerating chamber G is cooled by the walls ofthe evaporator G to an extent which is porportional to the surface of-these walls. The secondary or higher temperature evaporation in the bottom of the evaporator G is a. means of re 'lieving the-design of the evaporator of strict requirements as to the surface of the walls exposed to the refrigerating chamber G During the high temperature evaporation the refrigerating liquid is protected from heat relation with the ice chamber H by the vapors of the auxiliary agent in the same manner as the trays g are insulated from the walls of theevaporator G during the low temperature evaporation.

It will be noted that the high temperature just referred to is not due to any appreciable change in the composition of the cooling agent. In a literal sense a. small quantity of absorption liquor enters the evaporator G from the condenser C due to the fact that it is impracticable to return to the generator all of the vaporized absorption liquor by means of the rectifier E. There are, therefore, strictly speaking, two elements which form the cooling agent in the evaporator, the one element being the refrigerant which is. to be evaporated, and the other being a minute quantity of absorption liquor. This quantity of absorption liquor is normally so small that it does not appreciably change the evaporating temperature of the cooling agent even after much of the cooling agent. has been evaporated away, but it has a tendency to collect in the evaporator and if permitted to collect in any substantial quantity would result in a rise of temperature. To prevent this result, in the operation of the present system, the, elements in the liquid of the cooling agent are maintained in substantially the same weight proportion as in the vapor of the cooling agent by returning any unevaporated cooling agent in the bottom of the outer shell of the evaporator G to the absorber.

In addition to the function already mentioned such a return of unevaporated cooling agent limits the amount of cooling agent which may be abstracted during operation from the absorber generator system. This has the advanta e of preventing the absorption liquor from ecoming too weak for proper operation. In this way the quantity of cooling agent as distributed between the generator and the absorber is controlled by the amount present in the evaporator and con Sequently in accordance with the heat put into the generator. Such return is accomplished as shown herein for purposes of illustration only, by disposing the evaporator above the absorber.

The cooling agentis not only liberated The-absorber is so constructed as to promote absorption by the absorption liquor of the cooling agent at the surface of the liquor. Accordin 1y it is provided interiorly with a series of orizontal trays a a a, each of which is provided as at a, with an outlet which is raised slightly above the bottom of the tray soas to permit accumulation of the absorption liquor to a moderate depth.

The outlets at are sta gered so that the liquor flows over the w ole surface of the. trays, exposing a large surface for absorption of the auxiliary agent within the absorber. As the absorption liquor passes from one tray to the next below it and eventually to the bottom of the absorber vessel the means for the system, is introduced into the absorber at a convenient point, and is soldered to the underside of each tray-a a d, with many turns, and is eventually led from the absorber A, as at 0 passing through the pre-cooler and discharging as at o;- In this manner the vapor pressure of the absorbent ismaintained in conformity with the temperature of; the ultimate cooling means and below the pressure of the coolin agent in the gas mixture entering the absor er in a degree ap I reci-ably greater than that necessary to e ect absorption.

In operation it will be understood that a when heat is applied to the generator K the solution is raised from the generator into the separator K the ether or other cooling agent being at the same time separated from the absorption liquor, such vapor, being freed as far as possible from the absorption liquor, being then conducted to the condenser C where the vapor is condensed into liquid form and passes on through the evaporator G, such condensed liquid being practically pure ether, or what ever other cooling agent ma be employed. The liquid ether is distribute over the trays of the evaporator in the presence of the auxiliary agent, such as air or nitrogen or other suitable agent which is non-condensible at the temperature at which it operates and is inert with respect to the other chemical substances within the apparatus. In the presence of such auxiliary agent the ether or other 0001- g ing agent diifuses and evaporates, into thev auxiliary agent, heat being thereby abstractcd from th e surroundings while no change in actual or total pressure as between the condenser and the evaporatoris necessitated.

In this operation, as necessarily carried out in the apparatus shown in the drawings,

the absorption liquor is delivered to the generator K in an amount which exceeds the amount of absorption liquor delivered from the generator to the absorber by and only by the amount of cooling agent which is driven off from the absorption liquor in the generator. This relationis maintained through out the operation. If the amount ofabs orption liquor delivered to the generator should exceed the amount of absorption liquor de-' livered from the generator to the absorber by an amount greater than the amount of coolin agent driven off from the generator it would happen eventually that all of the absorption liquor would pass into the generator and the apparatus would cease to function. On the other hand if the excess of absorption liquor delivered to the generator should be less than the amount of. the cooling agent driven ofi in the generator theabsorption liquor would ac culnulate in the absorber and the system would cease to function. In other words, there is maintained, during the circulation of the absorption liquor between the generator and the absorber, a substantially constant level of absorption liquorin the absorber and a substantially constant level of absorption liquor in the enerator.

It will be 0 served that either nitrogen or air or some functionally equivalent agent maybe employed advantageously with ether as the cooling agent. Because such as auxiliary agent and such a cooling agent have specific and molecular weights which differ greatly with the result it is possible to obtain efiicient circulation and eflicient diffusion.

The ether vapor and auxiliary agent mingle in the evaporator and flow downwardly into the lower part of the absorber A where the gaseous mixture comes in contact with the weak absorption liquor supplied thereto from the separator K that is with the liquor in which there is dissolved a relatively less amount of the cooling agent, such liquor being preferably pre-cooled before it enters the absorber.

Through the established relation of the gaseous mixture and the absorption liquor there results an absorption or dissolvin of the ether by the absorption liquor and a li ration of the auxiliary agent. Since the auxiliary agent is of markedly diiferent specific weight than the cooling agent and is very much lighter than the cooling agent, it will be seen that the weight per unit volume of gas after it is freed from the ether or other cooling agent in the absorber is less than the weight per unit volume of the gaseousmix ture in the evaporator. 'As a result there will be a constant circulation of fluids between the absorber and the evaporator. v

' In the operation as thus described the head under which the movement takes place is produced rather by difference in the degree-of the mixture than by absolute separation of the elements and subsequent admixture. Some of the ether and other cooling agent passes upward through the pipe M from the absorber along-with the auxiliary agent to the evaporator, but the amount of cooling agent thus entrained is small relatively to the proportion of the cooling agent in the mix- .ture within the evaporator.

' Absorption liquor, saturated with the cooling agent, is carried from the absorber into the generator K under the influence of the heat applied to the generator. As vapor is formed within the generator it pockets some of the absorption liquor while it is escaping through the conduit 11 and such bodies of liquor will thereby belifted into-the upper part of the separator K The liquor thus displaced in the generator K is replaced by additional strong liquor from the absorber,

while the weaker liquor, which has been separated in the separator K ,runs by gravity back into theabsorber. Because of the fact that the circulation of the absorption liquor between the generator and the absorber is effected through'the generation of the cooling agent in.the generator, the circulation is more ra id when the process of vapor generation ecomes more rapid. In this way more absorption liquor is delivered to the absorber when more cooling agent is generated, condensed, evaporated, and delivered to the absorber. In other words the rate of delivery of the absorbent to the absorber is seen to be controlled in accordance with the amount of cooling agent delivered to the absorber, the economy and. effectiveness of which is manifest.

It will be seen that while the actual or total pressure in the apparatus remains at substantially atmospheric pressure, there is a varia tion as between partial pressures in the evaporator and absorber, the sum of which is equal to the actual or total pressure.

It will further be understood that as th apparatus functions at substantially atmospheric pressure the partial or difl'erential pressures of the cooling agent and the auxiliary agent are respectively below atmospheric pressure and that the lower the pressure of the cooling agent becomes the lower will be the temperature at which it will evaporate, the presence of the auxiliary agent not only permitting operation at constant total pressure, but if present in suflicient volume to exert sufficient partial pressure the cooling agent exerts a partial pressure low enough to permit it to evaporate. at freezing temperatures. Thus the auxiliary agent permits operation at a uniform/total pressure and operation at substantially atmospheric pressure, such atmospheric pressure being dependent to some extent upon the amount of auxiliary agent present.

It will also be seen that the total premure within the system is not only brought to that of the atmosphere but is also maintained "substantially constant at such atmospheric pres sure. This feature is not to be confused with the uniformity of pressure already referred to by which uniformity of pressure as between one meant.

It is desirable in the practical application of any refrigerating machine to operate throughout a range of evaporating temperatures which temperatures in turn present a range of evaporating pressures during operation. In the present invention operation over this range of evaporating pressures is not permitted to alter appreciably the total pressure within the system itself. This is accomplished by employing an auxiliary agent, the acting or partial pressure of which varies in accordance with the evaporating pressure of the'cooling agent to keep the total pressure constant. The variation is effected by the admission or withdrawal of auxiliary agent from or to a reservoir exterior to the system through the vent a. In the illustrated embodiment of the invention the reservoir is the atr'nos here itself. The vent q ispur osely placed as shown in the drawings at su stantially the point of exit of the auxiliary agent from the absorber, whereby only a negligible amount of cooling agent is permitted to escape from the system by reason of the process described. The feature of keeping the pressure substantially-constant within the system is an important one inasmuch as the full advantage of-atmospheric pressure operation is not realized unless light materials may be empart of the system and another is .ployed for construction and unless leakage of the cooling agent and absorption liquor may still be avoided. Differences of pressure of even a few pounds between the atmosphere and the pressure of the system are therefore to be avoided.

It will be observed that the operation of the system embodies the,circulation of the cooling agent from the generator, through the condenser, through the evaporator,

through the absorber and back to the generator; a local-circulation of the auxiliary agent between the evaporator and the absorber; and a local circulation of the absorption liquor between the generator and the absorber.

I claim as my invention:

1. The process of refrigerating which comprises'evaporating a liquid cooling agent of relatively low vapor pressure in the presence of an auxiliary agent inert to the cooling agent, producing a head, due to difference in specific weights of a mixture of the vapor of the cooling agent and the auxiliary agent on the one hand and the auxiliary afgent on the other hand, forcing the mixture -0 the vapor of the cooling agent and the auxiliary a cut under the influence of the head produced into the presence of an absorption liquor, absorbing the cooling agent in the absorption liquor,

withdrawing the absorption liquor from the presence of the auxiliary agent, returning the auxiliary agent into the presence of the cooling agent under the influence of the head produced, heating the absorption liquor and expelling the cooling agent from solution, returning the absorption liquor into the pres ence of the mixture, condensing the cooling agent, and returning the condensed cooling agent into the presence of the auxiliary agent these several steps of the process taking place in an apparatus open to the pressure of the atmosphere.

- 2. The process of refrigerating which comprises evaporating acliquid cooling agent of relatively low vapor pressure in the presence of an auxiliary agent inert to the cooling agent and having a specific weight lower than the specific weight-of the vapor of the cooling agent, producing a head due to difference in specific weights, forcing the mixture of the.

vapor of the cooling agent and auxiliary agent under the influence of the head produced into the presence of an absorption liquor, segregating the cooling agent from the auxiliary agent by absorption, and returning the auxiliary agent into the presence of the cooling agent under the influence of the head produced these several steps of the process taking place in an apparatus open to the presssure of the atmosphere.

3. The improve'mentin the'process ofre frigerating by the aid of a system including an evaporator and an absorber and open to the influence of atmospheric pressure which consists in diffusing a cooling agent which is in itself of relatively low vapor pressure, without admixture of an absorbent in the presence of an auxiliary agent in the evaporator, and

circulating the auxiliary agent through the evaporator and the absorber.

4:. The improvementin the process of refrig'erating by the aid of a system including an evaporator and an absorber and open to the influence of atmospheric pressure which consists in diffusing a'cooling agent of rela tively low vapor pressure in the presence of an auxiliary agent in the evaporator, and

circulating the auxiliary agent through the evaporator and the absorber exclusively by difference in specific weights of vertically extending bodies of fluid in the system.

5. The process of refrigerating which comprises evaporating aliquid cooling agent in the presence of an auxiliary agent at a relatively low temperature, facilitating through avoidance of inter-position of nonconductive matter; the heat transfer between the evaporating liquid and one portion of the space refrigerated, retarding through interposition of non-conductive matter the heat transfer between the evaporating liquid and a second portion of the space refrigerated, con tiruing the evaporation of the cooling agent in thepresence of the auxiliary agent at another point and at a higher temperature, facilitatin g heat transfer between the evaporating liquid and the second mentioned por-,

tion of the space refrigerated, retarding heat transfer between the evaporating liquid and the first mentioned ortion of the space refrigerated, introducing the mixed vapors. of the cooling agent and the auxiliary agent into the presence of an absorption liquor and absorbing the cooling agent therein, withdrawing the; absorption liquor with the cooling agent in solution therein from the presence of the auxiliary agent, returning the auxiliary agent into the presence of the liquid cooling agent, heating the absorption liquor with the cooling agent in solution and expelling the cooling agent from solution, returning the absorption liquor into the presence of the auxiliary agent and vaporized cooling agent, condensing the cooling agent, and returning the condensed cooling agent into the presence of the auxiliary agent.

6. The process of refrigerating which comprises evaporating a liquid cooling agent in the presence of an auxiliary agent at a relatively low temperature and at substantially atmospheric pressure, facilitating through avoidance of inter-position of non-conductivc matter the heat transfer between the evaporating liquid and one portion of the space refrigerated, retarding through interposition of non-conductive matter the heat transfer between the evaporating liquid and a second portion of the space refrigerated, continuing the evaporation of the cooling agent in the presence of the auxiliary agentat another point and at a higher temperature, facilitating heat transfer between the auxiliary agent into the presence of the liq-- uid cooling agent, heating the absorptionliquor with the cooling agent in solution and expelling the cooling agent from solution, returning the absorption liquor into the presence of the auxiliary agent and vaporized cooling agent, condensing the cooling agent,

and returning the condensed cooling agent into the presence of the auxiliary agent.

7. The process of refrlgerating which comprises evaporating a liquid cooling agent in I the presence of an auxiliary agent, transferring heat to the cooling agent from one portion of the space refrigerated, interposing. the mixture of thevapor of the cooling agent and the auxiliary agent between the evaporating liquid and said portion of the space refrigerated, transferring heat to the cooling agent'from a second portion of the space reh frigerated-without interposing the mixture of the presence of an absorption liquor and absorbing the cooling agent therein, withdrawing the absorption liquor with the cooling agent in solution therein from the presence of the auxiliary agent, returning the auxiliary agent into the presence of the liquid cooling agent, heating the absorptionliquor with the cooling agentin solution-and expelling the cooling agent from solution, returning the absorption liquor into the presence of the auxiliary agent an d vaporized cooling agent, condensing the cooling agent,and returning the condensed cooling agent into the presence of the auxiliary'agent.

8. The process'of refrigerating which comprises evaporating a liquid cooling agent substantially at atmospheric pressure inthe presence of an auxiliary agent, transferring heat to the cooling agent from one portion of the space refrigerated, interposing the mixture of the vapor of the cooling agent and the auxiliary agent between the evaporating liquid and said portion of the space refrigerated, transferring heat to the cooling agent from a second portion of the space refrigerated without interposing the mixture of the vapors of the cooling agent and the auxiliary agent, introducing the mixed vapors of the cooling agent and the auxiliary agent into the presence of an absorption liquor and absorbing the cooling agent therein, withdrawing the absorption liquor with the cooling agent in solution therein from the presence of the auxiliaryagent, returning the auxiliary agent into the presence of the liquid cooling agent, heating the absorption liquor with the cooling agent-in solution and expelling the cooling agent. from solution, returningf the absorption liquor into the presence of the auxilia condensing the cooling agent, and returning the condensed cooling agent into the presence Of the auxiliary agent.

9. The improvement in the process of refrigerating by the aid of a system including an evaporator and an absorber to receive an absorbent and open to the influence of atmospheric pressure, which consists in difiusing a liquid cooling agent of relatively low vapor pressure in the presence of an auxiliary agent, maintaining the elements of the liquid cooling agent in substantially the same weight proportion as in the. vapor of the cooling agent, delivering the mixture of the vapor of the coolin agent and the auxiliary agent to the absor ber, cooling the absorbent and thereby lowering the vapor pressure of the absorbent, absorbing the vapors of the coolin agent and returning the auxiliary agent into the presence of the liquid cooling agent.

10. The improvement in the process of reagent and vaporized cooling agent,

frigcrating by the aid of a system including an evaporator and an absorber to receive an absorbent and open to the influence of atmospheric pressure, which consists in diffusing a liquid cooling agent of relatively low vapor pressure in the presence of an auxiliary agent, maintaining the elements of the liquid cooling agent in substantially the same weight proportion as in the vapor of the cooling agent, delivering the mixture of the vapor of the cooling agent and the auxiliary agent to the absorber, cooling the absorbent and therebylowering the vapor pressure of the absorbent to conform with the temperature of the ultimate cooling means, absorbing the vapors of the cooling agent, and returning the auxiliary agent into the presence of the liquid cooling agent.

11. The improvement inthe process of refrigerating by the aid of a system including an evaporator and an absorber to receive an absorbent and open to the influence of atmospheric pressure, which consists in diffusing a liquid cooling agent of relatively low vapor pressure in the presence of an auxiliary agent, maintaining the elements of the liquid cooling agent in substantially? the same weight proportion as in the vapor-of the cool ing agent, delivering the mixture of the vapor of the cooling agent and the auxiliary agent to the absorber, cooling the absorbent and thereby lowering the vapor pressure of the absorbent, maintaining the vapor pressure of the absorbent in conformity with the temperature of the ultimate cooling means, absorbing the vapors of the cooling agent, and returning the auxiliary agent Into the presence of the liquid cooling agent.

12. The improvement in the process of refrigerating by the aid of a system including an evaporator. and an absorber to receive an absorbent and open to the influence of atmospheric pressure,;-which consists in diffusing pressure in-the-presence of an auxiliary agent,

. maintaining'theaelemehts of the liquid cooling agent in substantially the same Wei ht proportion as in the vapor of the cooling agent, delivering the mixture of the vapor of the cooling agent and the auxiliary agent to the absorber, cooling the absorbent and thereby lowering the vapor pressure of the absorbent, maintaining the vapor pressure of the absorbent below the pressure of the cooling agent in the gas mixture entering the absorber, absorbing the vapors of the cooling agent, and returning the auxiliary agent into the presence of. the liquid cooling agent.

13. The improvement in the process of refrigerating by the aid of a system including an evaporator and an'absofber to receive an absorbent and open to the influenceof atmospheric pressure, which consists in difiusing ,a liquid cooling agent of relatively low vapor pressure in the presence of an auxiliarv agent, maintaining the elements of the liquid cooling agent in substantially the same weight proportion as in the vapor of the cooling agent, delivering the mixture of the vapor of the cooling agent and the auxiliary agent to the absorber, cooling the absorbent and thereby lowering the vapor pressure of the absorbent, maintaining the vapor pressure of the absorbent below the pressure of the cooling agent in the gas mixture entering the absorber ina degree appreciably greater than that necessary to effect absorption, absorbing the vapors of the cooling agent, and returning the auxiliary agent into the presence of the liquid cooling agent.

14. The improvement in the process of refrigerating by the aid of a system including an evaporator and an absorber to receive an absorbent and open to the influence of atmospheric pressure, which consists in diffusing a liquid cooling agent of relatively low vapor pressure in the presence of an auxiliary agent, maintaining the elements of the liquid cooling agent in substantially the same weight proportion as in the vapor of the cooling agent, delivering the mixture of the vapor of the coolin agent and the auxiliary agent to the absor er, cooling the absorbent and thereby lowering the vapor pressure of the absorbent, absorbing the va ors of the cooling agent in the absorbent, withdrawing the absorbent from the presence of the auxiliary agent, heating the absorbent and expelling the cooling agent from the solution, and returning the absorbent into the presence of the mixture.

15. The improvement in the process of refrigerating by the aid of a system including an evaporator and an absorber to receive an absorbent and open to the influence of atmospheric pressure, which consists in diflt'using a liquid cooling agent of relatively low vapor pressure in the presence of an auxiliary agent, maintaining the elements of the liquid cooling agent in substantially the same weight proportion as in the agent, delivering the mixture of the vapor of the cooling agent and the auxiliary agent to the absorber, absorbing the vapors of the cooling agent in the absorbent, withdrawin the absorbent from the presence of the auxi iary agent, heating the absorbent and expelling the cooling agent from the solution, condensing the cooling agent, and returning the condensed cooling agent into the presence of the auxiliary agent.

16. The improvement in the process of refrigerating by the aid of a system including an evaporator, an absorber to receive an absorbent, and a generator and open to the influence of atmospheric presence, which consists in diffusing a liquid cooling agent of relatively low vapor pressure in the presence of an auxiliary agent, maintaining the elements of the liquid cooling agent in substantially vapor of the cooling the same weight pro ortion as in the vapor of the cooling a ent, elivering the mixture of the vapor of t e cooling agent and the auxiliary agent to the absorber, cooling the absorbent and thereby lowering the vapor pressure of the absorbent, delivering the absorbent to the generator in an amount exceeding the amount of the absorbent delivered from the generator to the absorber only by the amount of the cooling agent driven off in the generator, absorbing the vapors of the coolingagent, and returning the auxiliary agent into the presence of the liquid cooling agent.

17. The improvement in the process of refrigerating by the aid of a system including an evaporator, an absorber to receive an absorbent, and a generator and open to the influence of atmospheric pressure, which consists in diffusing a liquid cooling agent of relatively low vapor pressure in the presence of an auxiliary agent, maintaining the elements of the liquid cooling agent in substantially the same weight proportion as in the vapor of the cooling agent, delivering the mixture of the vapor of the cooling agent and the auxiliary agent to, the'absorber, cooling the absorbent and thereby lowering the vapor pressure of the absorbent to conform with the temperature of the ultimate cooling means, delivering the absorbent to the generator in an amount exceeding the amount of the absorbent delivered from the generator to the absorber only b the amount of the cooling agent driven 0 in the generator, absorbing the vapors of the cooling agent, and returning the auxiliary agent into the presence of the liquid cooling agent.

18. The improvement in the process of refrigerating by the aid of a system including an evaporator, an absorber to receive an absorbent, and a generator and open to the influence of atmospheric pressure, which consists in difiusing a liquid cooling agent of relatively low vapor pressure in the presence of an auxiliary agent, maintaining the elements of the liquid cooling agent in substantially the same weight proportion as in the vapor of the cooling agent, delivering the mixture of the vapor of the cooling agent and the auxiliary agent to the absorber, cooling the absorbent and thereby lowering the vapor pressure of the absorbent, delivering the absorbent to the generator in an amount exceeding the amount of the absorbent delivered from the generator to the absorber only by the amount of cooling agent driven oil in the generator, absorbing the vapors of the cooling agent, maintaining, during circulation of the absorbent between the generator and the absorber, a substantially constant level of absorbent in the absorber and a substantially constant level of absorbent'in the generator, and returning the auxiliary agent into the presence of the liquid cooling agent.

19. The improvement in the process of refrigerating by the aid of a system including an evaporator and an absorber to receive an absorbent and open to the influence of atmospheric pressure, which consists in delivering a gas mixture of the vapor of a cooling agent and an auxiliary agent to the absorber, cooling the absorbent and thereby lowering the vapor pressure of the absorbent to conform with the temperature of the ultimate cooling means, absorbing the vapors of the cooling agent, delivering the auxiliary agent to the evaporator, evaporating a cooling agent of relatively low vapor pressure in the presence of the auxiliary agent, and maintaining the elements of the liquid cooling agent in sub stantially the same weight proportion as in the vapor of the cooling agent.

20. The improvement in the process of refrigerating by the aid of a system including an evaporator and an absorber to receive an absorbent and open to the influence of atmospheric pressure, which consists in delivering a gas mixture of the vapors of the cooling agent and an auxiliary agent to the absorber, lowering the vapor pressure of the absorbent below the pressure of the cooling agent of the gas mixture in the absorber in a degree appreciably greaterthan that necessary to effect absorption, absorbing the vapors of the cooling agent, delivering the auxiliary agent to the evaporator, evaporating the cooling agent of relatively low vapor pressure in the presence of the auxiliary agent, and maintaining the elements of the liquid cooling agent in substantially the same weight proportion as in the vapor of the cooling agent.

21. The improvement in the process of refrigerating by the aid of a system including an evaporator and an absorber to receive an absorbent and open to the influence of atmospheric pressure, which consists in delivering a gas mixture of the vapors of the cooling agent and an auxiliary agent to the absorber, maintaining a gradation in the vapor pressure of the absorbent and at a substantially constant temperature throughout the absorber, absorbing the vapors of the cooling agent, delivering the auxiliary agent to the evaporator, evaporating the cooling agent of relatively low vapor pressure in the presence of the auxiliary agent, and maintaining the elements of the liquid cooling agent in substantially' the same weight proportion as in the vapor of the cooling agent.

'22. The improvement in theprocess of refrigerating by the aid of a system includingan evaporator, an absorber to receive an absorbent and a generator and open to the influence of atmospheric pressure, evhidr consists in evaporating a liquid cooling agent of relatively low vapor pressure in the presence, of an auxiliary agent, maintaming the elements of: the liquid cooling agent in substantiallythe same Weight pro portion as in the vapor of the cooling agent, delivering the mixture of the vapor of the cooling agent and the auxiliary agent to the absorber, cooling the absorbent and thereby lowering the vapor pressure of the absorbent to conform with the temperature of the ultimate cooling means, absorbing the vapors of the cooling agent, returning the auxiliary agent into the presence of the liquid cooling agent, heating the absorbent and expelling the coolin g agent therefrom, and maintaining during the operation a substantially constant quantity of cooling agent within the system.

23. The improvementin the process of refrigerating by the aid of a system including an evaporator, an absorber to receive an absorbent, and a generator and open to the in-' fluence of atmospheric pressure, which consists in evaporating a liquid cooling agent of relatively low vapor pressure in the presence of an auxiliary agent, maintaining the elements of the liquid cooling agent in substantially the same weight proportion as in the vapor of the cooling agent, delivering the mixture of the vapor of the cooling agent and the auxiliary agent to theabsorber, absorbing the vapors of the cooling agent, returning the auxiliary agent into the presence of the liquid cooling agent, withdrawing the absorbent from the presence of the auxiliary agent, heating the absorbent and expelling the cooling agent therefrom, return-- ing the absorbent with the cooling agent expelled therefrom into the presence of the auxiliary agent, and maintaining during the operation a quantity of cooling agent in the absorbent as distributed between the absorber and the generator varying only in amount by the quantity of cooling agent present in the evaporator.

24. The improvement in the process of refrigerating by the aid of a system including an evaporator, an absorber to receive an absorbent, and a generator and open to the influence of atmospheric pressure, which con-v sists in evaporating a liquid cooling agentof relatively low vapor pressure in the presence of an auxiliary agent, maintaining the elements of the liquid cooling agent in substantially the same weight proportion as in the vapor of the cooling agent, delivering the mixture of the vapor of the cooling agent and the auxiliary agent tothe absorber, absorbing the vapors of the cooling agent, returning the auxiliary agent into the presence of the liquid cooling agent, withdrawing the absorbent from the presence of the auxiliary agent,

heating the absorbent and expelling the cooling agent therefrom, returning the absorbent with the cooling agent expelled therefrom into the presence of the auxiliary agent, and controlling the quantity of cooling agent in the absorbent as distributed between the generator and absorber in accordance with the heat put into the generator.

4 of relatively low vapor pressurein the presence of an auxiliary agent, maintaining the elements of the liquid cooling agent in substantially the same weight proportion as in the vapor of the cooling agent, delivering the mixture of the vapor of the cooling agent and the auxiliary agent to the absorber, absorbing.

the vapors of the cooling agent, returning the auxiliary agent into the presence of the liquid cooling agent, withdrawing the absorbent from the presence 'of the auxiliary agent,

heating the absorbent and expelling the cooling agent therefrom, returning the absorbent with the cooling agent expelled therefrom into the presence of the auxiliary agent, and limiting'during the operation the quantity of cooling agent which may be removed from the absorbent as distributed between the generator and the absorber.

26. The improvement in the process of refrigerating by the aidiof a system. including an evaporator and an absorber to receive an absorbent and open to the influence of atmospheric pressure, which consists in evaporatmg a liquid cooling agent of relatively low vapor pressure in the presence of an auxiliary agent, maintaining the elements of the liquid cooling agent in substantially the same weight proportion as in the vapor of the cooling agent, delivering the mixture of the vapor of the cooling agent and the auxiliary agent to the absorber, absorbing the vapors of the cooling agent, returning the auxiliary agent into the presence of the liquid cooling agent, and controlling the rate of circulation of the auxiliary agent between the evaporator and the absorber in accordance with the refrigerating efi'ect required.

27. The improvement in the process of refrigerating by the aid of a system including an evaporator and an absorber to receive an absorbent, which consists in evaporating a liquid cooling agent in the presence of an auxiliary agent, maintaining during the operation the elements in the liquid of the cooling agent in substantially the same weight proportion as in the vapor of the cooling agent, delivering the evaporated cooling agent and the auxiliary agent to an absorber, absorbing the vapors of the evaporated cooling agent in the absorbent and thereby producing {further evaporation in the evaporator, returning the auxiliary agent into the presence of the unevaporated cooling agent, and maintaining within the system during the operation a pressure which is substantially the same at all times.

28. The improvement in the process of refrigerating by the aid of a system including an evaporator and an absorber to receive an absorbent, which consists in evaporating a liquid cooling agent, maintaining during the operation the elements in the liquid of the cooling agent substantially in the same weight proportion as in the vapor of the cooling agent, delivering the evaporated cooling agent to anabsorber, cooling the absorber .and thereby lowering the vapor pressure of the absorbent to conform with the -tempera-' 'ture of ultimate cooling means, absorbing the cooling agent, and maintaining within the, system during the operation a pressure which is substantially the same at all times.

29. The improvement in the process of refrigerating by the aid of a system including an evaporator and an absorber to recei\-e an absorbent, which consists in evaporating a. cooling agent in the presence of an auxiliary agent, maintaining during the operation the elements in the liquid of the cooling agent in substantially the sameweight proportion as in the vapor of the cooling agent, delivering the evaporated cooling agent and the auxiliary agent to an absorber, absorbing the vapors of the cooling agent, returning the auxiliary agent into the presence of the unevaporated cooling agent, and maintain ing within the system during the operation a pressure which is substantially the same at all times.

30. The improvement in the process of refrigerating by the aid of a system including the auxiliary agent to an evaporator, evaporating in the evaporator a liquid coohng agent of relatively low vapor pressure in the presence of the auxiliary agent, and main .taining during the operation the elements in the liquid of the cooling agent in substantially the same weight proportion as in the vapor of the, cooling agent.

31. The improvement 1n the process of refrigera'ting by the aid of a system including an evaporator, a space to be refrigerated, and an absorber to receive an absorbent and open to the influence of atmospheric pressure, which consists in evaporating a liquid cooling agent in the presence of an auxiliar agent, maintaining the elements in the liqui of the coolingagent in substantially the same weight proportion as in the vapor cooling agent, passing the mixed vapors of the cooling agent and the auxiliary agent through the space to be refrigerated and thereby removing heat from a heat emanating source within the space, delivering the mixed vapors to the absorber, cooling the absorbent and thereby maintaining the vapor pressure of the absorbent in conformity with the ultimate cooling means, absorbin the vapors of the cooling agent and there y producing further evaporation in the evaporator, returning the auxiliary agent to the evaporator, and maintaining within the system during the operation a. pressure which is substantially the same at all times.

This specification signed this 15th day of April, A. D. 1931.

' DONALD Bl KNIGHT. 

